Utilization of basic-event statistical independence in simplifying the uncertainty analysis of fault trees

Abstract EN

Analysis of fault trees used in modelling computer system security is typically based on orthogonalization of a Boolean expression as well as preservation of existing statistical independencies.

This note shows that careful utilization of statistical independencies is beneficial not only for evaluating the mean value of the top-event probability but also for quantifying its uncertainty.

A demonstrative example indicates that such utilization leads to a dramatic reduction in the number of coefficients calculated, as well as a significant simplification of the calculations needed for each of them